OSX Unrecognized Arguments Terminal Render
The issue isn't with Blender. It's with the command you're running. Using the open command is fine for opening applications, but it doesn't allow you to pass arguments to the application (as far as I know).

You want to call the executable directly with:
/Applications/Blender/blender.app/Contents/MacOS/blender "/Users/schultz/Desktop/Blender/slave.blend" --addons netrender -a -noaudio -nojoystick

Calling the executable itself will allow you to pass arguments to Blender.